I like the "Paleo" prescription from the reality POV.....tell someone to eat a certain way, and you are lucky to get 80% compliance. People drink beer/wine, eat cake, sip lattes, have bread, like pizza, take their kids out for ice cream, etc. If you give people too much leeway sometimes they end up fatter and wondering why down the road.

So it might be more ideal to start off giving strict rules (without needing an OCD way like the Zone), assume they are not going to be 100% compliant at all times and then let them adapt a new enjoyable lifestyle around it without guilt or feeling of being deprived (as that is why diets fail to work in the longterm....because no one stays on them).

Yeah, I feel this way too.

If you or your clients have the willpower to eat soundly from a nutrients perspective then go for it. I personally don't and I don't think 99.99% of people will either.